I find a baxandall circuit in the Internet but i don't understand how to calculate center frequency.
I want to calcute center frequency but it is difficulty for me.
Can anyone help me to calculate it??
I don't need a exactly result, i want to know relation of some components such as resistor, capacitor

 

Hello,

You already have a thread for this:
http://forum.allaboutcircuits.com/threads/graphic-equalizer-baxandall.102118/

Bertus